Agence France-Presse Tokyo Japan's industry minister expressed concern Tuesday about the impact of soaring iron ore prices and the growing concentration of the steel industry in the hands of a few companies.

Asia's top steelmakers said Monday they had agreed on a 65 percent rise in iron ore prices with Brazil's Vale to record levels, the sharpest gain in three years. The deal sets the benchmark for global prices.

"I am worried about the impact the prices will have on corporate management and the nation's economy," Akira Amari, Japan's minister of economy, trade and industry, told reporters."I want companies to make efforts on efficient operations so that product prices would not be affected," he said.

The price of iron ore, a key material in steel manufacture, has been driven up by a construction boom in Asia's fastgrowing emerging economies, particularly China and India.Amari also voiced concern about a growing oligopoly in the steel industry.

"I am concerned that prices may lose flexibility if specific materials become increasingly dominated by certain companies," he said.

The Arcelor-Mittal deal left Japan's Nippon Steel as the world's second largest steelmaker. Nippon Steel and South Korea's POSCO said Monday they had jointly reached the accord on iron ore prices with Brazilian leader Vale.

Japan, which is the world's second largest economy but lacks natural resources, imports all of its iron ore, with 60 percent coming from Brazil.

Japan's top automaker Toyota Motor Corp. said Monday it had no immediate plans to raise the price tag on its cars despite the growing steel costs.